1. Technical Field
The present disclosure relates to a hearing aid and a feedback canceller.
2. Related Art
A general hearing aid includes a microphone for collecting sound transferred from external space and a receiver for outputting sound to a user's ear canal. During usage of the hearing aid, sound output from the receiver may be fed back to the microphone to cause howling. To suppress such occurrence of howling, there is a known feedback canceller using an adaptive filter configured to adaptively estimate a feedback transfer function, as a device used for a hearing aid and feedback canceller including a structure capable of suppressing occurrence of howling (refer to JP-A-6-130968, for example). In general, an especially low-frequency band component is input into this kind of feedback canceller, the adaptive filter is likely to perform unstable operations. To solve this problem, JP-T-2002-526961 discloses a feedback canceller having a filter (high-pass filter or band-pass filter) for removing a low-frequency band component that is inserted into the stage preceding an adaptive filter. In addition, JP-A-2011-254468 discloses a feedback canceller having a fixed filter for modeling an unchanged portion of a feedback path that is inserted into the stage preceding an adaptive filter.